An Israel/Iran war could bring in the US and the UN on the side of Israel and Russia/the other middle eastern countries that hate Israel (95% of them) on the side of Iran.

a lot of the middle east have their own issues with each other tho, the likelihood of them uniting is highly unlikely. let alone uniting to fight us since we're on pretty good terms with almost half of them. and a lot of them have issues with Iran as well...